The longitudinal follow-up study is divided into a characterization and longitudinal phase. During the characterization subjects will undergo a baseline evaluation that will include will include answering questionnaires, lung function testing, and chest tomography. Subsequently, to determine steroid responsiveness, all subjects will receive one intramuscular dose of 40 mg in 1ml (1 mg/kg for children <18 years old, up to 40 mg maximum. Participants at the University of Pittsburgh will undergo a bronchoscopy to provide airway samples. The longitudinal phase will include a 36 month follow-up time with annual visits and phone calls every 6 months. During it, participants will answer questionnaires and provide sputum samples on two occasions, and will perform lung function testing.